//1.创建Koa对象
const koa = require('koa')
const app = new koa()
//2.编写响应函数(中间件)
app.use((ctx,next) =>{
    console.log(ctx.request.url);
    ctx.response.body = '111'
})
//3.绑定端口号  3000
app.listen(3000)